1. Field of the Invention
The present invention relates to a multi-band compatible multi-antenna device and communication equipment, and more specifically to a multi-band compatible multi-antenna device including a plurality of antenna elements and communication equipment including such a multi-band compatible multi-antenna device.
2. Description of the Related Art
Multi-band compatible multi-antenna devices including a plurality of antenna elements have been conventionally known (see Japanese Patent Application Laid-Open Publication No. 2008-29001, for example).
The aforementioned Japanese Patent Application Laid-Open Publication No. 2008-29001 discloses a multi-band compatible MIMO antenna (multi-antenna device) including two antenna elements. Each of the antenna elements of this MIMO antenna includes a first radiating plate, a second radiating plate, and a PIN diode that can electrically link the first radiating plate and the second radiating plate to each other, and the PIN diode is configured so as to be able to switch by switching control to either a state in which the first radiating plate and the second radiating plate are linked to each other or a state in which the first radiating plate and the second radiating plate are separated from each other. Thus, as a result of the use of switching control to link or separate the first radiating plate and the second radiating plate, the full length of each antenna element is switched, thereby the MIMO antenna of Japanese Patent Application Laid-Open Publication No. 2008-29001 is compatible with different frequency bands.
However, with the multi-band compatible MIMO antenna of Japanese Patent Application Laid-Open Publication No. 2008-29001, while different frequency bands can be handled by switching the full length of each antenna element using switching control, there is a problem in that the MIMO antenna cannot be miniaturized because the distance between the antenna elements needs to be large so as to reduce an amount of the interconnection between the antenna elements.